weston



(No Model.) 3' Sheets-Sheet 1.

E. WESTON.

RHBOSTAT.

No. 269,760. Patented Dec. 26, v1.882.

F SCALE.'

ff/L9@ g ed@ zu@ (No Modelv.) 3 Sheets-Sheet '2.

E. WESTON.

RHEOSTAT. l1To. 269,760. Patented Deo. 26, 1882.

WX W W M 4 Q S H @I e e e Q Wm 3 Sheets-Sheet 3.

(No Model.)

E. WESTON.

RHBOSTAT.

Patented Deo. 26, 1882.

UNITED STATES PATENT OFFICE.

EDWARD IVESTON, OF NEWARK, NEW JERSEY, ASS-SIGNOR TO THE UNITED STATESELECTRIC LIGHTING COMPANY, OF NEW YORK, N. Y.

RHEOSTAT.

SPECIFICATION forming part of Letters Patent No. 269,760, datedDecemberv 26, 1882.

A pplieation lcd August 3l, ISSQ. (No model.)

To au whom it may concern Be it known that I, EDWARD WESTON, a subjectof the Queen of Great Britain, and a resident of Newark, in the countyof Essex and State ot' New Jersey, have invented certain new and usefulImprovements in Rheostats, of which the following is a specification,refer. ence being had to the drawings accompany ing and forming a partof the salue.

The object ot' my improvements is chieiiy to render more durable andserviceable rlieos tats containing conductors in the shape of ribbons orstrips; and the improvements consist in the combination, with saidconductors, under the conditions hereinafter specified, of springs ortheir eqnivalents,for the purpose of maintaining the conductors underconstant tension, and thereby preventing contacts between adjacentportions of the same when expanded by heat.

In the drawings I have illustrated my invention as applied to a rheostatot' well-known construction, by reference to which the gen- Veral natureof the improvements will he understood.

Figure l represents in elevation a rheostat constructed according to myinvention. Fig.

2 is a portion of the same enlarged,exhibiting the mechanicalconstruction in detail. Fig. 3 is an end view, partly in section; andFig. 4, a top view, showing the indicatingscale and sliding contacts.

Similar letters indicate corresponding parts in the several figures.

A A designate the vertical supports of the apparatus, by which issupported a wide board, B, constituting a base, upon which theresistance devices are mounted. In a line along the upper edge of theboard B, and as close together as practicable, are clamped devices forholding the ribbon-conductor. These consist of brass castings C, formingbrackets, andare clamped to the board B by screws c c. D D are theportions ot' the castings that serve as contact-surfaces.

E E are pins, of iron orother metal,that are held in place by thecastings O and plates of brass F F, clamped to the outer ends of thecastings U. l

Along the lower cud of the board B, and corresponding in number andposition to the cast ings G G, are clamped the brass castings orbrackets G Gr. Stout spiral springs S S are made fast to the oppositeends of the bars gol' the brackets G, and their free ends united to pinsH H, and are preferably insulated from them in any convenient manner.

The conductor consists otl a long dat strip or ribbon, L,of Germansilver or other proper metal. One end is secured to the pin E oftheiirst casting, C, on either side, and it is then 6o carried alternatelyunder the pins H and over the pins E in order until all the upper andlower brackets are connected and the rheostat presents the appearanceshown in Fig. l. In practice it will be found desirable to solder thepins E E to the strip after having measured ed' the proper distances,then to secure thepins E in place, and, lastly, to insert the pins H Hin the folds or convolutions of the strip and fasten the springs S S tothem. The 7o rst one of the series of upper brackets, C, is connected bya thick metal strip with a biliding-post, K, and on the opposite side ofthe board are arranged brackets, contacts, and a ribbon, exactlycorresponding to those described, K being the binding-post of theopposite series ol" resistances.

Along the upper edge of the board B is a metal guide, M, of suitablekind, upon which is arranged to slide a metal block, N. Plates 8o P l,depending from either side of block N, carry brushes R R, and abinding-post, T, is setin the block N. Along the metal guide M,preferably on its upper surface, one or more scales are marked, by whichthe variations in resistance corresi'ionding to different positions ofthe block N are ascertained. If one end of a severed circuit beconnected with the binding-post T and the other end witheitherbinding-post K or K', the resistance will be in- 9o creased by theintroduction into the circuit of so much conductor as lies between anytwo ot' the brackets for each bracket or casting C that is touched bythe brush R. On the other hand, it' the ends of a circuit be connectedto posts 95 K K', double the resistance is brought into circuit forevery casting that is encountered by the contact-brushes.

Heretofore serious difficulties have been met with in the use of devicesef this kind. The roo heating of the strips by a powerful currentexpands and distorts them, so that a number of short circuits are likelyto result. By the use ot' the springs S, however, these obstacles to theaccurate and successful operation ot' the apparatus are entirelysurmounted.

1t may be stated that in lieu ofthe springs weights may be used; but theconstruction described is believed to be the most conven- Io ient.

It is also possible, without departure from my invention, to use agreater or a less number of springs for taking up expansion. This is,however, a matter that the necessities of particular cases must govern.

What I claim as my invention is- 1. In an electrical rheostat,thecombination, with the conducting strips or ribbons, ot' springsconnected to the said strips in such zo manner as to prevent contact. ofadjacent porducting strip or ribbon L, ot' the brackets G G and spiralsprings S S, all substantially as herein set forth.

In testimony whereof I have hereunto set my hand this 30th day ot'August, 1882.

EDVARI) VESTO.

Witnesses:

W. Frusnr, RAYMOND F. BARNns.

